Base is a layer made out of relatively fine materials with size between 0 to 20mm and is used to attain following objectives:
Functions of Base in Rail Lines:
- Reducing the stresses applied in infrastructure layers;
- Maintaining the upper level of the bed against penetration of ballast rocks;
- Protecting the infrastructure level against frost;
- Preventing the penetration of fine particles of pavement platform into ballast;
Higher facility of drainage.
Functions of Base in the Road:
Base is the second pavement layer of the road and its performance is adjusting the loads applied from upper layers of pavement when transferring to the sub-base layer such that the permissible stress applied cannot make impermissible subsidence and or deformation. Base has higher permeability properties than sub-base layer and comprised from aggregates and or a mixture of aggregates and adhesive materials with given technical specifications. This layer must tolerate the axial load as well as road’s drainage load.